Cerebellar Function 1809 – The Little Brain

Whenever you see a ballet dancer, martial artist or pianist, you should thank the cerebellum, a walnut-sized region with a ridged surface beneath the cerebral hemispheres and behind the brainstem.

The name cerebellum comes from the Latin word cerebellum, meaning “little brain”. The cerebellum is a small structure at the back of the brain involved in motor coordination, balance and the regulation of movement. More functions have been discovered in recent years. Its name therefore reflects both its smaller size relative to the brain and its important functions. 

• In 1809, the Italian anatomist Luigi Rolando observed that damage to animals' cerebellums caused clear disturbances in their movements. 
• In 1824, the French physiologist Jean Pierre Flourens conducted further experiments showing that animals with damaged cerebellums could still move, but their movements were awkward and uncoordinated. Flourens proposed that the cerebellum coordinates movements but does not initiate or consciously plan them.

Today, we know that the cerebellum integrates nerve signals from the ear (its labyrinthine region, which supplies information about body orientation for balance) and the muscles to facilitate movement, and also plays a role in language perception and emotional responses.

Anatomically, the cerebellum's left and right hemispheres are joined by a structure called the “vermis”. The cerebellum also contains more than 50% of all the brain's neurons in the form of small cerebellar granule cells. Because the cerebellum has so many folds, only about one-sixth of it is visible from the outside.

Besides controlling muscle movements, the cerebellum influences personality formation and immediate emotional states. Recent research suggests that patients with an abnormal cerebellum or cerebellar lesions may experience impaired speech fluency, depression, autistic-like obsessive rituals and difficulty understanding social life. 

About the Article Image: Resembling a smaller version of the brain in size and structure, the cerebellum is a central nervous system organ at the lower back of the brain. Like the brain, it has two hemispheres. Although it accounts for one-tenth of the brain's weight, it contains about half of the brain's neurons.

Historical Figures Mentioned in the Article: Luigi Rolando (1773–1831), Marie Jean Pierre Flourens (1794– 1867)

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